1. Field of the Invention
The present invention relates to a coating composition and a substrate coated with the coating composition. More particularly, the present invention relates to a coating composition that imparts high gloss, good slip properties, low extractables and appealing aesthetic properties to a substrate coated with the composition. The coated substrate can subsequently be used to form various articles of manufacture that require or would benefit from such properties, including, for example, feminine hygiene products, food-grade products, and the like.
2. Description of Related Art
There exist numerous applications that require a product to possess both highly functional properties in conjunction with highly aesthetic properties. This is especially true with consumer products, where the consumer is not only concerned with how well the particular product functions, but also how the product looks and feels. Another important consideration when making a consumer product is regulatory constraints, which oftentimes restrict the materials from which a product can be formed.
In particular, feminine hygiene products, such as tampons, and food-related products are subject to above-identified constraints, making it extremely difficult to make a product that is highly functional, meets the aesthetic demands of the consumer, and meets any regulatory guidelines.
With regard to tampon applicators, it is widely known that they are generally formed from either a molded thermoplastic material, such as plastic, or a paper laminate, such as cardboard or paperboard.
Molded plastic applicators can be formed with a high degree of surface smoothness, which results in increased comfort during insertion of the tampon applicator. In addition, the molded plastic applicator can be easily modified to include a color, pearlescence, and the like, by modifying the thermoplastic prior to molding. However, plastic tampon applicators, unless certain expensive plastics are used, are neither water dispersible or biodegradable. In an ecology minded society, biodegradability is desired.
To achieve biodegradability, a cardboard or paper laminate applicator is preferred since it delaminates upon saturation with water, thereby facilitating biodegradation. However, a film laminated paper applicator is difficult to form with a perfectly circular cross-section, and the degree of circularity of the laminated paper applicator has been found to further degrade during the tube forming heating stage of the manufacturing process. Moreover, the cardboard applicator must be modified to reduce the coefficient of friction for ease of insertion. In addition, consumers typically find cardboard applicators to be less aesthetically pleasing over their plastic counterparts.
To address both the need for a reduction in the coefficient of friction of the cardboard applicator, some commercially sold cardboard applicators have applied thereto either a separate film laminate bonded by adhesive, or a liquid coating which then solidifies.
A polyester film coating, which has been used on commercially sold tampon applicators, has been found to shrink during the heating cycle of the applicator manufacturing process, causing the distortion of the applicator's shape thereby increasing the ejection force. A cellophane film also shrinks due to the evaporation of water absorbed from the adhesive used to apply it to the applicator. Further, cellophane is usually coated with a water-resistant coating, such as nitrocellulose. Nitrocellulose coating of cellophane is expensive, and requires the use of a volatile organic solvent to apply the coating. The use of such a solvent requires special handling and disposal procedures, all of which further raise manufacturing costs.
Liquid coated paper laminate applicators are known in the art. For example, U.S. Pat. No. 4,412,833 to Weigner et al. is directed to an applicator formed of a high-gloss paper that can be coated with a degradable, dispersible or water soluble polymer, such as a modified polyethylene, polypropylene, polyvinylidene chloride or polyvinyl alcohol. U.S. Pat. No. 4,508,531 to Whitehead provides an applicator with a heat-sensitive coating, such as polyolefin (e.g., polyethylene or polypropylene) or a heat sensitive adhesive.
However, neither the liquid nor film coatings applied to the prior art cardboard tampon applicators described above have permitted the combination of formation of the desired reduction in friction, glossy finish, retention of applicator circularity, and sufficient biodegradability, let alone while further providing enhanced aesthetics to the applicator. Further, some prior art liquid coatings are more expensive, and require the use of organic solvents, leading to increased manufacturing cost and consumer cost.
The present invention overcomes the difficulties in providing additional aesthetic properties to a substrate and/or product without compromising the functional properties of the substrate or product, while still meeting regulatory requirements. This is accomplished by providing a low extractables coating that imparts additional properties such as, for example, low coefficient of friction, high gloss, color, and/or pearlescence to the substrate coated with the composition. As a result, a highly functional product having enhanced aesthetics is efficiently produced without compromising any of the desired functional properties.